A vacuum



T'. Tissus. PROCESS AND APPARATUS FOR PRODUCING AND MMNTAINFNG A VACUUM.

APPLICATION FILED DEC.24| IB-l?.

Patented Aug. 29,

A TTOHNEYS y rUNITED STA'LE PATENT OFFICE.;

THOMAS TIBBETS, OF ELLICOTT-CITY,%M.A.RYLAND, ASSIGNOR OF THREE-FURTHS` T0 f JOHN C. TIBBETTS, 0F EIZILICOT'I CITY, lMARYLAND.

PROCESS AND .APPARATUS FOR ).ROIDUCITG'-y ANDYMAINTAINING 1A VACUUM.

Specification of Letters Patent- Pttelltd A1-lg; 29, 1922 Application filed December 24,1917. Serial No. 208,597.

i To all whom t may concern Be it known thatI, THOMAS TriiBnTs, a citizen of the United States, and a resident of Ellicott City, in the county of Howard and State of Maryland, have invented' a neu7 and useful Improvement 'in Processes and Apparatus yfor'` Producing and" Main- LYmaintaining a vacuum, and it consists 'in' `taining a Vacuum, of u ihichthefolloiving' is a specification.

. My invention relates to improvements' inV f process and apparatus for producing and litho'steps hereinafter pointed' out, andthe means for accomplishing the same. Y

"An object of my invention 'is to provide an improved processv whereby a partial vacuum'may beproduced andV maintained,

and in Which the necessity formechanical" devices such-y as pumps, condensers, etc. is eliminated. v

Av furt-her object of my invention isfto provide a process which may be 'carried out with any ordinary boiler, by the addi-' tion of a U-shaped tube or pipe which may be attached to the boiler or built in with it.

A further object of my invention is to providea process for providing and maintaining a vacuum or reduction of pressure which requires no attention/to keep the system in order. V

Other objects and advantages will appear in the following specification, and thenovel features of the invention will be particu-I larly pointed out in the appended claims.

My invention is illustrated'inthe accompanying drawings forming' apart vof thisv application, in which Figure 1 is a section througha boiler' constructed according to my'invention, and Figure 2 is a diagrammatic view of a steam heating system to which myiniproved process and apparatus are applicable.

t My yinvention is applicable to use .1n Which a. partial vacuum` is" desired. It'

is, .particularly .adapted Afor VVmaintaining a vacuum in steam heat-ing'systems. I have,

therefore described such ajsysteinto illus` trate my invention.

In carrying out my invention I. make" s use cfa-ny 'suitable boiler. l In the drawings .this boiler' is shown as havingv a base l, an ashc pit 2, ay grate 3, a combustion vcham- .ber' 4, an outlet 5f for exhaust gases', and

1a `Water aclret 6. ASurmounting the"'Water fjacket is-a steamdome 7.

'connection 9 with a vertically ext `pipe 10.

' ilotvrinto the pipe 10.

."lhe parts mentioned thus far are -to be found in'ordinary types of boilers and constitute no part of the present invention cooperate With the parts described, to produce novel to say, With the bottom' of .the boiler, at

one'end,- and at the other end with a 'pipe v13, this pipe 13 being the return pipe from the radiators 14. The pipe 13, as will be' observed, communica-tes Withthe pipe' 10,

a check valve 15 being interposed so that a 'rearward flow, thatis to say, from the pipe 10 to thepipe 13 is prevented. The pipe 10 also communicates With 'the pipel having a check valve 18 rto' prevent back v`'In Figure 2 I have shown a steam pipe 19 'connected ivith the steam dome 'of' the 'boiler and leading to the radiators '14, .these 'radiators being' connected bythe return pipe 13, in the manner shown.

From the foregoing description ofthe various parts of the' device the operation thereof may be readily understood.

Fire is started in the combustion chamber l in the usual manner and the' heat from .'thefuel around tube S causes steam to form v at that point in the tube, which rises through it tothe surface of the Water in the steam dome 7. In rising it lifts a portion ofthe Water. in tube 8 With'it, which lcauses vthe Water 'initubes 9 and 10 to 'be drawn-'after it-and' the surface of the' Water in tube -10 to fall. As soon as the steam escapes ('.from the tube Sthe balancing of Weight of 'the water intubes 8, 9 and '10 causes: Water "from the` steam dome to be draWninto vthe tube 8 andthe surface of the Water intube '10.toi" rise again. .This action 'i'recurs in a 'fairly regular manner, ycausing-the surface of' the Water in tube. 10 to rise and ,fall alf tern'ately and to act asa liquid-piston. p

lllhenthe surface Vof lthe Water falls in tube 10 the check valve 15 Willbe pulled open,"the valve 1S will Adrop shut. and;A air Will escape from pipe 13 into pipe 10. l/Vlienthe'surface of the Water. 'in pipe 10 rises the 'check-valve 15 `vyilldrop shut, thus` preventing the return of air into pipe 13,

` the checlr"\f'alve 18 willv be'pushed open `and air will be forcedout of pipeilO tothe atmosphere. This actionis made continuous so long as the recurrent formation of steam takes place .in pipe S. lt causes a reduction of pressure or partial vacuum in the system,

'y or a partial vacuum which is entirely suiii- "cient to successfully operate a steam heating plant maybe maintained by the arrangement just described. One of the important features of this arrangement is that it is automat-ic.4 f`

I lind in practice that when the temperature of the water in the boiler is consideral'ilyj Y below the boilingpoint, if the draft is kept 'y works at such times and by the suction it` 'g'Oing vspecific maybe n'sedw.'

11i whchfthefre ehllratiorr of air. i OIdesirable.

produces'assists in the elimination of air and reduces the pressure at the return end of the system.` But its apparently maximum effectr is produced when the water in the `boiler .is-'below the boiling point, or merely vaporizing. At such times air meets with no resistance in `entering they ordinary. system and itseliniination is most important so that the system may be filled withlower temperature `vapor when a ,low temperature is desired. In other words, yif the system is economically designed, in very cold weather a certain amount of pressureis needed. The v pressure! at` the boiler end andthe suction vof the U-tube pump atthe other end pro- ,mote vthe circulation of steamv very efficiently and the action of the pump eliminates the air. In moderately cold weather when no pressureiis' needed in the system, the action of the U-tube,l pump is `most needed and jf, is under just ysuch'conditions that yits actiOAn is most apparent. s, p Y U yyhilefl have shown one formjof 'the deis obvious that other forms might be 'ecf 17in thtipri; departing from the spirit of el i. structure' described in the foreration and in the annexed claims duction of` pressure or the in the system is necessary 'n furth el 'explan it will be noted ,that

",wo legs of af U-tube, the heated pipe 8,

end with an enopening at the top ofn onefvertical legor tube, a circulation of water will be started ith vany steam heating system' t. ation cof my improved y larged receptacle, in the present illustration the steam dome 7; lt is a wel] known fact that it water contained in two vertical tubes connected at thetopand bottom and upon the application ofheat to the open leg and this circulation will continue up the heated leg, across the top, down the unheated leg and across thebottom to .the heated leg. flhis is caused by the waterin the heated leg expanding and thus becoming lighter. The more the ywater is hea-,ted the faster the circulating movement thereof, and when the `water is heated to` such an extent that steamis formed, the mixed water and steamin the heated leg is still lighterand thedcirculating movement is greatly accelerate Should the connection at thetops of theI two vlegs be removed andtheir upperends separated as in the present instance1 the mixed water` and steam in the heated leg will Vflow upward and spread out within the recepy :tac/le at the topnamely the steam dome 7,

and the water in the unheated leg will flow down until mostof theA steam escapes from the heated leg, whereupon .the weight of the column of water in t-he'heated leg overcomes that of the lowered column` in the unheated leg and a reverse movement takes place as the water flows down `the heated leg and up the unheated leg. Because of the proportionately greater area of the receptacle lat the `top of the heated leg as `compared to that of the leg itself, the water naturally spreads vicio out,` over this area and the length of the I water column is notpincreased except to an extremely slight degree so that the formation of steam-in the heated column and the escape of this steam from the vwater at the surface abo-ve the heated leg" thus makes, for

the moment, an unbalanced or differential `weight or pressure with an immediate consequentfshortening ofthe column of water in the unheated leg to balance.

l claim: p A

LThe process of producing and maintaining a vacuumwithin a container by applying heatto one leg of a Ueshaped tube connected Ito the container, to cause the rise and fall of ayliquid contained in the tube,

applying this force to draw `air from the container and to discharge it into the at mosphere, and at the same time preventing a reverse movement of the air.'

2. The herein described process of maintaining a vacuum withinv ay container which consists inv applying heat tothe 4water in one column of a U-shaped tube whose other column is connected'to'the"container, .thereby causing the level of the water in the latter column to rise and fall, allowing air in the ycontainer to take the "placeof the rarefiedair y in the latter column when the level ofthe "i sage of air from the container into the connecting arm, but preventing the reverse flow .f of the air, and a check valve carried by said connecting arm near the top thereof, for permitting the exit of air from the connecting arm and for preventing the entrance of air into the connecting arm from the outer atmosphere.

4:. In a device for maintaining a vacuum, a container pipe, a boiler, a U-shaped tube having a short arm communicating with the boiler below the level of the water, the longer arm of said U-shaped tube projecting above the level of the liquid, said longer arm having near its upper end an outlet into the outer atmosphere and said container being connected with the longer arm of the tube near said outlet, a check valve at the junction of the container with the long arm, for permitting the passage of air from the l container into the long arm but for preventing a reverse iow of the air, and a check valve carried by the long arm, for permitting the exit of air from the long arm into the outer atmosphere, but preventing the reverse flow.

5. The combination with a steam boiler, of a container, and means in connection with the boiler and actuated thereby during normal operation of the boiler for pumping a portion of the air out of the container, whereby to maintain a partial vacuum on the container.

6. The combination with a steam boiler having a steam dome, of a container connect-4 ed with the bottom of the boiler, means carried by the boiler for pumping a portion of the airqout of the container, thereby maintaining a partial vacuum on the container, said means comprising a U-shaped tube having a shortarm and a long arm, the short arm oi3 the tube being connected with the bottom of the steam dome beneath the level of the water, and the long arm extending above the level of the water, a connection between the container. and the long arm, means for permitting a flow of air from the container into the long arm and means for permitting a iiow of air from the long arm to the outer atmosphere while preventing a reverse iiow.

7. The process of producing and maintaining a vacuum in a container by intermittently withdrawing air from the container through the torce of the alternate rise and fall of a fluid in a U-shaped tube having heat applied at or near the base of one vertical leg.

8. An apparatus comprising a U-shaped tube adapted to contain a liquid, means for heating one arm of the U-shaped tube, for causing fluctuation of the level of the liquid in the arms of the tube, and a valve connected with the other arm of the tube for permitting the discharge of air from the tube and for preventing the returning oit air, thus discharged to the tube.

9. An apparatus comprising a U-shaped tube adapted to contain a liquid, means for heating one arm of the U-shaped tube to cause fluctuation of the level of the liquid in the other arm of the tube, a container, a connection between the container and the last mentioned arm of the tube, and means for permitting the flow of air from the container into the last mentioned arm of the tube and from the latter to the atmosphere, while preventing a reverse How.

I THOMAS TIBBETS.

Vitnesses:

J.'HARTLEY JOHNSON, R. O. VVoo'rnN. 

